The present invention relates to a brake fluid pressure controller with a motor-driven hydraulic pump necessary for antilock control and track control of vehicle wheels, and more specifically to a brake fluid pressure controller having an improved structure for sealing between the pump-driving motor and the housing of a hydraulic unit coupled to the motor.
This type of brake fluid pressure controller has an electric motor for driving the hydraulic pump mounted in the housing of the hydraulic unit. The motor is directly mounted on the housing. As disclosed in Unexamined Japanese Utility Model Publication 4-86063, the motor is usually fixed to the housing by inserting through bolts through the rear end cover of the motor and the space between a rotor and a yoke, and threadably engaging the housing.
The brake fluid pressure controller is mounted in the engine room of a car. If the controller is mounted at a lower part of the engine room, the controller must be highly waterproof. It is possible to completely seal the rear portion of the motor by forming the end cover of the motor and the cylindrical portion of the yoke as an integral member, or by welding the end cover to the cylindrical portion of the yoke. What is difficult a seal is to seal the contact area between the housing of the hydraulic unit and the motor.
Heretofore, in order to completely seal the contact area and thus to improve the waterproofness of the entire controller, the opposite surfaces of the motor and the housing were brought into contact with each other after increasing their flatness by cutting. But with this method, it is practically impossible to perfectly seal the contact area because it is difficult to obtain flat surfaces by cutting. Thus, water may infiltrate into the contact area between the housing and the motor, and then into the motor through gaps around the through bolts and the output shaft of the motor, or into the housing through a hole formed in the housing for receiving the output shaft of the motor.
In order to make the housing/motor interface more watertight, as shown in FIG. 3, it was necessary to provide seal rings 8 such as 0-rings to seal any gap around the output shaft 5 of the motor and the through bolts 7.
If the seal rings 8 are used, it is necessary to form seating grooves 9 by cutting to receive the seal rings 8 in the housing 3 of the hydraulic unit 2 to protect the seal rings by limiting their interference. Further, mounting mount a plurality of seal rings one by one is a troublesome and timeconsuming job. Since many rings are used, some of are frequently omitted by oversight.
An object of the present invention is to provide a brake fluid pressure controller which has a seal member which can be mounted easily and reliably.